Coupling



FIG. 1 is perspective view of the coupling.

FIG. 2 is a side view of the coupling; and,

FIG. 3 is a left end view of the coupling of FIG. 2.

The dashed broken lines in the drawing depict portions of the coupling that form no part of the claim. The dash-dot broken lines define the boundaries of the claim and form no part thereof. 

CLAIM The ornamental design for a coupling, as shown and described. 